Climate
change in Europe. 1. Impact on terrestrial ecosystems and biodiversity. A
review

Abstract - Ecosystems have an essential role in providing services to humankind such as
nutrient cycling, pest control, pollination, quality of life, and
hydrological, atmospheric and climatic regulation. About 60% of the
world's known ecosystems are currently used unsustainably. In Europe, the
richness and abundance of biodiversity is undergoing significant decline,
partly due to climate change. This article outlines the impacts of climate
change on biodiversity by showing both observed and projected changes in the
distribution and phenology of plants and animals (phenology refers to
changes in the timing of seasonal events). The four major findings are the
following.
(1) Concerning the distribution of plant species, climate change is
responsible for the observed northward and uphill distribution shifts of
many European plant species. By the late 21st century, distributions of
European plant species are projected to have shifted several hundred
kilometres to the north, forests are likely to have contracted in the south
and expanded in the north, and 60% of mountain plant species may face
extinction. The rate of change will exceed the ability of many species to
adapt.
(2) Concerning plant phenology, the timing of seasonal events in plants is
changing across Europe due to changes in climate conditions. For instance,
78% of leaf unfolding and flowering records show advancing trends. Between
1971 and 2000, the average advance of spring and summer was 2.5 days per
decade. The pollen season starts on average 10 days earlier and is longer
than 50 years ago. Trends in seasonal events will continue to advance as
climate warming increases in the years and decades to come.
(3) Concerning the distribution of animal species, Europe's birds, insects,
and mammals are moving northwards and uphill in response to observed climate
change. Rate of climate change, habitat fragmentation and other obstacles
will impede the movement of many animal species. Distribution changes are
projected to continue. Suitable climatic conditions for Europe's breeding
birds are projected to shift nearly 550 km northeast by the end of the
century. Projections for 120 native European mammals suggest that up to
9% face extinction during the 21st century.
(4) Concerning animal phenology, climatic warming has caused advancement in
the life cycles of many animal groups, including frogs spawning, birds
nesting and the arrival of migrant birds and butterflies. Seasonal
advancement is particularly strong and rapid in the Arctic. Breeding seasons
are lengthening, allowing extra generations of temperature-sensitive insects
such as butterflies, dragonflies and pest species to be produced during the
year. These trends are projected to continue as climate warming increases in
the decades to come. Populations may explode if the young are not exposed to
normal predation pressures. Conversely, populations may crash if the
emergence of vulnerable young is not in synchrony with their main food
source or if shorter hibernation times lead to declines in body condition.